JP5806787B1 - Method for manufacturing dummy liner and cylinder block - Google Patents

Abstract

A dummy liner capable of reducing dimensional accuracy is provided. Prior to casting a cylinder block, a dummy liner that is cast instead of a cylinder liner until the temperature of the mold rises from an inner peripheral surface of a cylindrical portion into which a bore pin is inserted. A protruding portion 23 protruding radially inward contacts the outer peripheral surface 15 of the bore pin 14. A radial gap 24 is formed between the inner peripheral surface 22 of the cylindrical portion 21 and the outer peripheral surface 15 of the bore pin 14 except for the protruding portion 23. Since the molten metal filled in the radial gap 24 does not adhere to the bore pin 14, high dimensional accuracy that prevents the gap between the bore pin 14 and the dummy liner 20 from being generated can be eliminated. Therefore, the dimensional accuracy of the dummy liner 20 can be relaxed. [Selection] Figure 4

Description

  The present invention relates to a dummy liner used for preheating a mold for manufacturing a cylinder block, and a method for manufacturing a cylinder block using the dummy liner.

  Conventionally, an aluminum alloy cylinder block in which an iron-based cylinder liner is cast has been manufactured. Prior to casting the cylinder block, the mold is preheated in order to improve the water temperature. As a means for preheating the mold, a dummy liner for disposal is mounted on the bore pin, which is a cylindrical convex part on the mold side where the cylinder liner is mounted, and the cavity formed by clamping the mold is made of an aluminum alloy. There are those that inject molten metal. The mold is preheated by casting a discarded piece integrated with the dummy liner.

  When the injected molten metal enters the gap between the bore pin and the dummy liner, the molten metal solidifies, and when the discarded product is removed from the mold, the solidified material of the molten metal collapses (breaks) and remains on the surface of the bore pin. The solidified product sandwiched between the discarded product and the bore pin may be rubbed against the bore pin and stick (fixed) to the bore pin. If the solidified substance is fixed to the bore pin, when the product (cylinder block) cast after the preheating of the mold is taken out, the product is caught by the solidified substance fixed to the borepin to become resistance, or the mold (bore pin) is damaged. A malfunction occurs.

  In order to prevent this problem from occurring, Patent Document 1 discloses that in a preheating process in which a dummy liner is attached to a bore pin and a molten metal is injected, the casting pressure is reduced and the injection speed is reduced to form a gap between the dummy liner and the bore pin. A technique for preventing the molten metal from entering is disclosed. In Patent Document 2, a dummy liner having an axial length longer than that of a cylinder liner is used, and both end surfaces in the axial direction of the dummy liner are clamped between the first die and the second die, and the bore pin and the dummy liner are A technique for preventing the molten metal from entering the gap is disclosed.

Japanese Patent Publication No. 6-47160 Japanese Patent No. 4444615

  However, in the above conventional technique, it is necessary to prevent the gap between the bore pin and the dummy liner from occurring in order to prevent the molten metal from entering the gap between the bore pin and the dummy liner. Since the dummy liner is required to have high dimensional accuracy, there is a problem that the cost of the dummy liner is increased.

  The present invention has been made to solve the above-described problems, and an object thereof is to provide a method for manufacturing a dummy liner and a cylinder block that can reduce dimensional accuracy.

Means for Solving the Problems and Effects of the Invention

  In order to achieve this object, a dummy liner according to claim 1 includes a first mold that forms part of a deck surface side molding cavity, a second mold that forms part of a crank chamber molding cavity, and a first mold thereof. For casting a cylinder block made of an aluminum alloy in which a cylinder liner is cast by a mold having an axial bore pin disposed between the second mold and the first mold and in contact with an inner peripheral surface of the cylinder liner. Prior to this, casting is performed instead of the cylinder liner until the temperature of the mold rises to a predetermined temperature. When the present inventors intentionally provided a gap (radial gap) between the inner peripheral surface of the metal dummy liner and the outer peripheral surface of the bore pin, the molten metal that has entered the radial gap does not adhere to the bore pin. I found.

  According to this dummy liner, the protruding portion that protrudes radially inward from the inner peripheral surface of the cylindrical portion into which the bore pin is inserted is in contact with the outer peripheral surface of the bore pin. A radial gap is formed between the inner peripheral surface of the cylindrical portion and the outer peripheral surface of the bore pin except for the protruding portion. The molten metal is filled from the gap in the radial direction, and crystal grains are refined by contact with the bore pin and rapidly solidified, so that the solidified molten metal can be prevented from adhering to the bore pin.

  In addition, the solidified product that has solidified due to the molten metal intruding into the radial gap has a thickness equivalent to the radial gap, so that a certain degree of strength can be secured, and the solidified product can be removed when removing the discarded product from the mold. Can be made difficult to collapse. As a result, it is possible to suppress the collapsed solidified product from being sandwiched between the thrown away product and the bore pin and being rubbed against the bore pin, so that the solidified product can be prevented from adhering to the bore pin.

  As described above, the dummy liner prevents the solidified material from adhering to the bore pin by providing a radial gap between the bore pin and the molten metal to be positively filled with molten metal. There is no need to increase accuracy. Since the dimensional accuracy of the dummy liner can be relaxed, there is an effect that the cost of the dummy liner can be reduced.

In addition, the protruding portion is formed in a ridge shape that continues in the axial direction of the cylindrical portion. Since the cross-sectional shape orthogonal to the axial direction can be made the same across the axial direction, a dummy liner can be made by cutting a long object formed by extrusion molding or pultrusion molding. Therefore, there is an effect capable of ensuring the production of Da Miraina.

Since the protruding portion is formed in a ridge shape that extends continuously in the axial direction of the cylindrical portion, a circumferential gap formed between the protruding portion and the protruding portion extends across the axial direction of the cylindrical portion. Can be provided. Since the solidified product of the molten metal that has entered the gap can be continued in the axial direction of the cylindrical portion, the solidified product can be further prevented from collapsing when the discarded product is removed from the mold. Therefore, it is possible to further enhance the effect of not sticking the melt was solidified coagulation in bore pins.

According to the dummy liner of claim 2 , the cylindrical portion has an axial gap formed between at least one of the first mold and the second mold whose axial length is clamped and the end face in the axial direction. It is set to a length. Therefore, in addition to the effect of the first aspect, there is an effect that the molten metal can be easily poured into the radial gap from the axial gap between the axial end surface of the dummy liner and the first mold or the second mold.

According to the cylinder block manufacturing method of the third aspect, the first mold that forms part of the deck surface side molding cavity, the second mold that forms part of the crank chamber molding cavity, and the second mold A cylinder block in which the cylinder liner is cast is manufactured by a mold including a bore pin that is disposed between the mold and the first mold and is in contact with the inner peripheral surface of the cylinder liner. The cylinder liner is mounted on the bore pin, the mold is clamped with the cylinder liner disposed between the first mold and the second mold, and the molten aluminum alloy is formed in the cavity including the deck surface side forming cavity and the crank chamber forming cavity. Prior to injecting the mold, the mold is heated by the preheating process until the temperature of the mold rises to a predetermined temperature. In the mold clamping process, the dummy liner according to claim 1 or 2 is mounted on the bore pin, and the mold is clamped in a state where the dummy liner is disposed between the first mold and the second mold. A casting process in which the molten liner is cast between the outer peripheral surface of the bore pin and the inner peripheral surface of the cylindrical portion of the dummy liner by injecting the molten metal into the cavity formed by the mold clamping process. The product is cast. Thus, the same effect as in the first aspect is obtained.

  Patent Document 1 and Patent Document 2 disclose a method for manufacturing a dummy liner and a cylinder block that have the same technical field as the present invention, but both prevent molten metal from entering the gap between the dummy liner and the bore pin. This technology prevents the molten metal from sticking to the bore pin. On the other hand, in the present invention, the protruding portion provided on the inner peripheral surface of the cylindrical portion of the dummy liner is brought into contact with the outer peripheral surface of the bore pin, and the protruding portion is removed between the inner peripheral surface of the cylindrical portion and the outer peripheral surface of the bore pin. Therefore, it differs from Patent Documents 1 and 2 in that a gap (radial gap) is formed and the molten metal is positively filled. Since the solidified product of the molten metal filled in the radial gap provided between the dummy liner and the bore pin does not adhere to the bore pin, the solidified product can be prevented from adhering to the bore pin. Since the radial gap is provided between the dummy liner and the bore pin, the dimensional accuracy of the dummy liner can be reduced.

It is a bottom view of a part of cylinder block. It is sectional drawing of the cylinder block in the II-II line | wire of FIG. (A) is a sectional view in the axial direction of the mold, and (b) is a sectional view of the mold in which a portion indicated by IIIb in FIG. 3 (a) is enlarged. (A) is sectional drawing of the metal mold | die in the IVa-IVa line | wire of FIG. 3, (b) is sectional drawing of the metal mold | die in the IVb-IVb line | wire of Fig.4 (a). (A) is a front view of the dummy liner in 1st Embodiment, (b) is a front view of the dummy liner in 2nd Embodiment.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings. FIG. 1 is a bottom view of a part of a cylinder block 1 according to an embodiment of the present invention (a view of the deck surface viewed from the crank chamber side in a direction orthogonal to the crank axis direction). It is sectional drawing of the cylinder block 1 in the II-II line. The cylinder block 1 is an aluminum alloy die cast in which a cast iron cylinder liner 2 having excellent wear resistance is cast, and a bearing wall whose center on the crank chamber side is recessed in a semicircular shape on the bottom surface on the crank chamber side. 3 is provided. The bearing wall 3 is a portion that rotatably supports a journal portion of a crankshaft (not shown). The bearing wall 3 is formed in a plate shape whose thickness direction is the axial direction (the left-right direction in FIG. 1) of the crankshaft, and a plurality of the bearing walls 3 are arranged at intervals along the axial direction of the crankshaft. The bearing wall 3 is formed with screw holes 4 on both sides for connecting the cylinder block 1 to a crankcase (not shown).

  With reference to FIG. 3, a discarded part for preheating and a mold 10 for casting the cylinder block 1 will be described. The discarded product has the same shape as the cylinder block 1 and is an aluminum alloy die cast in which dummy liners 20 and 30 (to be described later) are cast instead of the cylinder liner 2, and thus illustration is omitted. 3A is an axial cross-sectional view of the mold 10, and FIG. 3B is a cross-sectional view of the mold 10 in which a portion indicated by IIIb in FIG. 3A is enlarged.

  The mold 10 includes a movable mold 11, a fixed mold 12, a movable core 13, and a bore pin 14 fixed to the movable mold 11. 3 (a) and 3 (b) illustrate a state in which a dummy liner 20 is attached to the bore pin 14 prior to casting the cylinder block 1, and a discarded product in which the dummy liner 20 is cast is to be cast. ing.

  The movable die 11 constitutes a part of a deck surface side molding cavity 16a for forming the deck surface side of the cylinder block 1, and a jacket wall portion 17 for molding the water jacket into the cylinder block 1 is provided. It is formed in a cylindrical shape. The fixed die 12 constitutes a part of a crank chamber forming cavity 16b for forming a crank chamber of the cylinder block 1, and a bulging portion 18 for forming the crank chamber is formed. The bore pin 14 is formed in a cylindrical shape and protrudes from the movable mold 11 toward the fixed mold 12.

  The dummy liner 20 attached to the bore pin 14 will be described with reference to FIGS. 4 (a), 4 (b) and 5 (a). 4A is a cross-sectional view of the mold 10 taken along the line IVa-IVa in FIG. 3, and FIG. 4B is a cross-sectional view of the mold 10 taken along the line IVb-IVb in FIG. FIG. 5A is a front view of the dummy liner 20 in the first embodiment (viewed from the direction of the axis O). In FIG. 5A, the bore pin 14 is indicated by an imaginary line (two-dot chain line).

  As shown in FIG. 4A, the dummy liner 20 is attached to the bore pin 14 prior to casting the cylinder block 1 to cast an aluminum alloy discarded product (not shown) in which the dummy liner 20 is cast. This is a metal member for preheating the mold 10. In the present embodiment, the dummy liner 20 is integrally formed of an aluminum alloy.

  As shown in FIG. 5A, the dummy liner 20 includes a cylindrical portion 21 that is formed in a cylindrical shape, and a protruding portion 23 that protrudes radially inward from the inner peripheral surface 22 of the cylindrical portion 21. . The cylindrical portion 21 is a portion into which the bore pin 14 is inserted, and a cross section perpendicular to the axis O is set in an annular shape. As shown in FIGS. 4A and 4B, the cylindrical portion 21 provides a gap (radial gap 24) between the outer peripheral surface 15 of the bore pin 14 and the inner peripheral surface 22 of the cylindrical portion 21, The inner diameter is set to be 2 to 6 mm larger than the outer diameter of the bore pin 14. The cylindrical portion 21 has a radial thickness of 1 to 5 mm in order to avoid mechanical interference with the mold 10 (see FIG. 3A) while ensuring mechanical strength.

  Returning to FIG. 3A and FIG. When the movable liner 11 and the fixed die 12 are clamped by attaching the dummy liner 20 to the bore pin 14, the cylindrical portion 21 is in a state where the axial end surface 25 of the cylindrical portion 21 is in contact with the movable die 11. The axial length is set so that a gap of 0 to 20 mm (axial gap 27) is formed between the end face 26 in the direction and the bulging portion 18 (the gap of 0 mm has no axial gap 27). Means that).

  As shown in FIGS. 4A and 4B, the protruding portion 23 is a portion for positioning the cylindrical portion 21 in the radial direction with respect to the bore pin 14. If the projecting portion 23 is not provided, the dummy liner 20 is moved by the injected molten metal, the inner peripheral surface 22 of the cylindrical portion 21 contacts the outer peripheral surface 15 of the bore pin 14, and the radial gap 24 is in the contacted portion. Cannot be secured. Since the protruding portion 23 is provided in the cylindrical portion 21, the radial gap 24 can be secured between the inner peripheral surface 22 of the cylindrical portion 21 and the outer peripheral surface 15 of the bore pin 14 except for the protruding portion 23.

  The projecting portion 23 has a radial clearance 24 formed between the inner peripheral surface 22 of the cylindrical portion 21 and the outer peripheral surface 15 of the bore pin 14 by contacting the distal end in the radial direction with the outer peripheral surface 15 of the bore pin 14. Projecting radially inward from a plurality of locations (at least 3 locations, 8 locations in the present embodiment) of the cylindrical portion 21 that are evenly allocated in the circumferential direction. In the cross-sectional shape perpendicular to the axis O, the protruding portion 23 has a slightly smaller inscribed circle diameter in contact with the radially inner tip of the protruding portion 23 than the outer diameter of the bore pin 14 (in this embodiment, 1 to 1). 2mm) is set larger. The dummy liner 20 mounted on the bore pin 14 shrinks in the radial direction due to casting pressure or solidification of the molten metal and cannot be removed from the mold, or the protruding portion 23 of the dummy liner 20 that shrinks in the radial direction due to solidification of the molten metal rubs against the bore pin 14 strongly. This is to prevent being taken. The protruding portion 23 is formed in the shape of a ridge that extends parallel to the axis O and extends in the axial direction of the cylindrical portion 21.

  The dummy liner 20 is formed in a direction perpendicular to the axial direction after an elongated tubular body (not shown) in which the cylindrical portion 21 and the protruding portion 23 are continuously formed in the axial direction is formed by extrusion molding or pultrusion molding. It is manufactured by cutting every predetermined length. Since a plurality of dummy liners 20 can be manufactured by cutting a long tubular body at a plurality of locations, the productivity of the dummy liners 20 is superior to that obtained by casting the dummy liners 20 one by one. Since the cylindrical portion 21 has a radial thickness of 1 to 5 mm, the cutting operation can be easily performed. Further, since the dummy liner 20 has the same cross-sectional shape perpendicular to the axis O on both sides in the axial direction, there is no designation in the mounting direction to the bore pin 14 (which of the end faces 25 and 26 in the axial direction is directed toward the movable mold 11). . Therefore, it is possible to prevent a misdirection when the dummy liner 20 is attached to the bore pin 14.

  Returning to FIG. 3 (a), a method for manufacturing a discarded article for preheating the mold 10 will be described. After the dummy liner 20 is mounted on the bore pin 14, the movable mold 11, the fixed mold 12 and the movable core 13 are clamped in a state where the dummy liner 20 is mounted on the bore pin 14 (mold clamping process). The protruding portion 23 contacts the outer peripheral surface 15 of the bore pin 14, thereby forming a radial gap 24 of 1 to 3 mm on one side between the outer peripheral surface 15 of the bore pin 14 and the inner peripheral surface 22 of the cylindrical portion 21 (see FIG. 4 (a)). The cylindrical portion 21 has an axial clearance 27 of 0 to 20 mm between the axial end surface 26 and the bulging portion 18 in a state where the axial end surface 25 of the cylindrical portion 21 is in contact with the movable mold 11. (There is no gap when the axial gap is 0 mm). When the movable mold 11, the fixed mold 12, and the movable core 13 are clamped, a cavity 16 including a deck surface side molding cavity 16a and a crank chamber molding cavity 16b is formed.

  Next, a molten aluminum alloy is injected into the cavity 16 (casting process). The molten metal injected into the cavity 16 flows into the radial gap 24 between the bore pin 14 and the dummy liner 20 from the end face 26 side of the dummy liner 20 while forming the bearing wall 3 (see FIGS. 1 and 2), and the end face of the dummy liner 20. Reach 25. After the molten metal cools and solidifies, the movable mold 11, the fixed mold 12 and the movable core 13 are opened, and the discarded product in which the dummy liner 20 is cast is taken out from the mold 10.

  Next, it is determined whether or not the temperature of the mold 10 is higher than a predetermined temperature suitable for casting of the cylinder block 1, and when the temperature of the mold 10 is equal to or higher than the predetermined temperature, casting of a discarded product (preheating process) ) Ends. When the temperature of the mold 10 is lower than the predetermined temperature, the casting of the discarded product is repeated until the temperature of the mold 10 becomes equal to or higher than the predetermined temperature. Since the mold 10 is preheated before the cylinder block 1 is cast, the amount of hot water can be improved, and the occurrence of defects in the cylinder block 1 cast after the mold 10 is preheated can be suppressed. Further, since the discarded article is cast using the dummy liner 20 made of the same type of aluminum alloy as the material of the cylinder block 1, when the discarded article is used as the return material, the work of separating the dummy liner 20 can be omitted. Therefore, it is possible to easily reprocess the discarded product as the return material.

  According to the dummy liner 20, the protruding portion 23 is in contact with the outer peripheral surface 15 of the bore pin 14, so that the diameter of the protruding portion 23 is excluded between the inner peripheral surface 22 of the cylindrical portion 21 and the outer peripheral surface 15 of the bore pin 14. A directional gap 24 is formed. The molten metal filled in the radial gap 24 exists around the bore pin 14 (excluding the protruding portion 23) along the axial direction of the dummy liner 20. Since the molten metal in contact with the movable mold 13 and the bore pin 14 is rapidly cooled and solidified, the crystal grains are refined, so that the molten metal solidified in the radial gap 24 can be prevented from being fixed to the bore pin 14.

  In addition, the solidified material (not shown) that is solidified by filling the radial gap 24 with molten metal has a thickness corresponding to the radial gap 24, so that a certain degree of strength can be secured, and the discarded product is made of gold. When taken out from the mold 10, the solidified product can be made difficult to collapse (hard to tear). As a result, it is possible to prevent the collapsed solidified product from being sandwiched between the thrown away product and the bore pin 14 and being rubbed against the bore pin 14, so that the solidified product can be prevented from adhering to the bore pin 14. As a result, when the product (cylinder block 1) cast after preheating the mold 10 is taken out, the cylinder block 1 is caught by the molten metal (solidified material) fixed to the bore pin 14 to become resistance, or the mold 10 (bore pin 14). It is possible to prevent problems such as damage.

  Here, when casting a discarded product so that the molten metal does not enter the gap between the dummy liner 20 and the bore pin 14 (Patent Documents 1 and 2), in order to make the gap between the bore pin 14 and the dummy liner 20 as small as possible, The dummy liner 20 is required to have high dimensional accuracy. However, in this embodiment, since the radial gap 24 can be intentionally provided between the dummy liner 20 and the bore pin 14, the dimensional accuracy of the dummy liner 20 can be relaxed. As a result, the manufacturing cost of the dummy liner 20 can be reduced.

  Further, when casting a discarded product so that the molten metal does not enter the gap between the dummy liner 20 and the bore pin 14 (Patent Document 1), casting pressure, injection speed, etc. for casting so that the molten metal does not enter the gap. It is necessary to determine the conditions. However, in the present embodiment, the casting conditions that allow the molten metal to be filled in the radial gap 24 that is intentionally provided suffice, so that the discarded product can be cast even under the conditions for casting the cylinder block 1. Therefore, it is not necessary to set conditions for casting a discarded product. In addition, since a discarded product can be cast under conditions for casting the cylinder block 1 (mass production conditions), the dummy liner 20 can be used for determining the conditions for casting the cylinder block 1 (for mass production).

  When both ends of the dummy liner are continuously brought into close contact with the bore pin in the circumferential direction so that the molten metal does not enter between the dummy liner and the bore pin (Patent Document 2), the dummy liner is accompanied by solidification contraction of the molten metal injected into the cavity. When contracted, both ends of the dummy liner are continuously rubbed in the circumferential direction (in a ring shape) and rubbed against the bore pin, so that the aluminum material of the dummy liner tends to stick to the bore pin (is easily fixed). On the other hand, according to the present embodiment, the dummy liner 20 is provided with the protruding portions 23 intermittently provided in the circumferential direction, so that the dummy liner 20 is contracted as the molten metal injected into the cavity 16 is solidified and contracted. In addition, the contact area between the protruding portion 23 and the bore pin 14 can be reduced. Therefore, the aluminum material of the dummy liner 20 can be hardly fixed to the bore pin 14.

  In particular, since the dummy liner 20 has a cross-sectional shape orthogonal to the axis O, the diameter of the inscribed circle in contact with the radially inner end of the protruding portion 23 is set larger than the outer diameter of the bore pin 14. The contact area between the projecting portion 23 and the bore pin 14 when contracted can be made zero or minute. Therefore, it is possible to prevent the protruding portion 23 from being rubbed against the bore pin 14 due to the shrinkage of the dummy liner 20 accompanying the solidification shrinkage of the molten metal, and the aluminum material of the dummy liner 20 being fixed to the bore pin 14.

  Since the protruding portion 23 is formed in the shape of a ridge that extends parallel to the axis O and extends in the axial direction of the cylindrical portion 21, a circumferential clearance formed between the protruding portion 23 and the protruding portion 23. Can be provided over the axial direction of the cylindrical portion 21. Since the solidified product of the molten metal that has entered the gap can be continued in the axial direction of the cylindrical portion 21, the strength of the solidified product is ensured, and the solidified product is removed when the discarded product is taken out from the mold 10. It can be made difficult to collapse. Since the collapsed solidified product can be prevented from being sandwiched between the discarded article and the bore pin 14 and rubbed against the bore pin 14, the solidified product can be prevented from adhering to the bore pin 14.

  A radial gap 24 formed between the outer peripheral surface 15 of the bore pin 14 and the inner peripheral surface 22 of the cylindrical portion 21 by bringing the protruding portion 23 into contact with the bore pin 14 is 1 to 3 mm on one side. When the radial gap 24 is 1 mm or more on one side, the radial gap 24 is not clogged due to solidification, so that the flow of the molten metal in the axial direction from the end face 26 side to the end face 25 side is in the middle of the radial gap 24. It can be prevented from stopping. When the molten metal is rapidly cooled and solidified after the radial gap 24 is filled, the structure of the surface in contact with the bore pin 14 can be made dense, so that the molten metal can be prevented from adhering to the bore pin 14. When the radial gap 24 is 3 mm or less, although depending on the outer diameter of the dummy liner 20, the radial thickness of the cylindrical portion 21 is secured while avoiding interference between the dummy liner 20 and the mold 10 (movable core 13). As a result, the mechanical strength of the dummy liner 20 can be prevented from being lowered.

  The cylindrical portion 21 has a shaft of 0 to 20 mm, preferably 1 to 5 mm between the axial end surface 26 and the bulging portion 18 in a state where the axial end surface 25 of the cylindrical portion 21 is in contact with the movable mold 11. A direction gap 27 is formed. Compared with the case where the dummy liner 20 is sandwiched between the movable mold 11 and the bulging portion 18, the end surfaces 25 and 26 of the dummy liner 20 are prevented from being pressed against the movable mold 11 and the bulging portion 18. The part 18 can be prevented from being damaged. If the axial gap 27 is 1 mm or more, the molten metal injected into the cavity 16 can be poured into the radial gap 24 not only from the portion of the bearing wall 3 but also from the axial gap 27. The amount of molten metal that enters the gap 24 can be secured. When the axial gap is 5 mm or less, axial movement of the dummy liner 20 disposed between the movable mold 11 and the fixed mold 12 can be suppressed.

  Next, a second embodiment will be described with reference to FIG. In the first embodiment, the case where the outer peripheral surface of the cylindrical portion 21 is formed in a circular shape in the cross section perpendicular to the axis O of the dummy liner 20 has been described. On the other hand, in the second embodiment, a case where the concave portion 35 is formed on the outer peripheral surface 34 of the cylindrical portion 31 of the dummy liner 30 will be described. In addition, about the part same as the part demonstrated in 1st Embodiment, the same code | symbol is attached | subjected and the following description is abbreviate | omitted. FIG. 5B is a front view (a view seen from the direction of the axis O) of the dummy liner 30 in the second embodiment.

  As shown in FIG. 5B, the dummy liner 30 includes a cylindrical portion 31 formed in a cylindrical shape, and a protruding portion 33 that protrudes radially inward from the inner peripheral surface 32 of the cylindrical portion 31. Is an aluminum alloy member formed integrally. The cylindrical portion 31 is a portion into which the bore pin 14 is inserted, and a cross section orthogonal to the axis O is set in an annular shape. The protruding portion 33 has a radial clearance 24 formed between the inner peripheral surface 32 of the cylindrical portion 31 and the outer peripheral surface 15 of the bore pin 14 by the radial tip contacting the outer peripheral surface 15 of the bore pin 14. Projecting radially inward from a plurality of locations (six locations in the present embodiment) of the cylindrical portion 31 that are evenly allocated in the circumferential direction. The protruding portion 33 is formed in a ridge shape that is parallel to the axis O and continues in the axial direction of the cylindrical portion 31.

  The cylindrical portion 31 is recessed toward the radially inner side (thickness direction of the cylindrical portion 31) on the outer peripheral surface 34 corresponding to the circumferential position (three of the six locations) where the protruding portion 33 is provided. A recess 35 is formed. The concave portion 35 is formed in a groove shape that is parallel to the axis O and continues in the axial direction of the cylindrical portion 31. The concave portion 35 has a cross-sectional curve orthogonal to the axis O that is smoothly formed continuously from the cylindrical portion 31 to the concave portion 35 on the outer peripheral surface 34 of the cylindrical portion 31, so that the molten metal that has flowed around the dummy liner 30. It is possible to suppress local deformation in the vicinity of the recess 35 due to solidification.

  The concave portion 35 is formed on the outer peripheral surface 34 corresponding to the protruding portion 33 formed on the inner peripheral surface 32. The protrusions 33 and the recesses 35 are set to have substantially the same radius of curvature of the cross-sectional curve orthogonal to the axis O, so that the radial thickness of the cylindrical portion 31 is significantly reduced by forming the recesses 35. Can be prevented. Therefore, it is possible to prevent a decrease in mechanical strength of the dummy liner 30 due to the formation of the recess 35.

  According to this dummy liner 30, since the concave portion 35 is formed on the outer peripheral surface 34 of the cylindrical portion 31, the material constituting the dummy liner 30 is reduced by the amount of the concave portion 35 compared to the dummy liner in which the concave portion 35 is not formed. Can do. Further, when the dummy liner 30 is mounted on the bore pin 14 of the mold 10 using a loading device (not shown) such as a robot hand, the nail of the loading device can be put into the recess 35 and the dummy liner 30 can be gripped. Problems associated with handling of the carry-in device can be suppressed. Further, the cylindrical portion 31 can be easily expanded and contracted in the circumferential direction by the concave portion 35 as compared with the dummy liner in which the concave portion 35 is not formed. Since the cylindrical portion 31 can be expanded and contracted in the circumferential direction by the concave portion 35 when an external force due to the solidification of the molten metal flowing around the dummy liner 30 is applied to the dummy liner 30, a discarded product in which the molten metal around the dummy liner 30 is solidified. It can be suppressed that it becomes difficult to remove the mold by biting into the bore pin 14.

  Hereinafter, the present invention will be described specifically by way of examples. In the following embodiments, by changing the height of the protruding portion 23, the radial gap 24 between the cylindrical portion 21 and the bore pin 14 and various dummy liners 20 having different radial thicknesses of the cylindrical portion 21 are used, and discarded. Product and cylinder block 1 were tried. In addition, this invention is not limited to a following example.

(Example 1)
A dummy liner 20 made of an aluminum alloy (A6063S) in which the length of the cylindrical portion 21 in the axial direction is 126 mm and the diameter of the inscribed circle in contact with the protruding portion 23 is 91 mm (extruded from a tubular body and cut along a plane perpendicular to the axis) Was mounted on a bore pin 14 having an outer diameter of 90 mm and the mold 10 was clamped, and then a molten aluminum alloy was injected to cast a discarded product. After repeating this three times, a cast iron cylinder liner was mounted on the bore pin 14 to cast the aluminum alloy cylinder block 1.

  The dummy liner 20 has an axial length (126 mm) that is the same or shorter than the axial dimension of the cavity 16 by 1.5 mm. The thickness of the cylindrical portion 21 of the dummy liner 20 was 3 mm, and the radial gap 24 (one side) between the inner peripheral surface 22 of the cylindrical portion 21 and the outer peripheral surface 15 of the bore pin 14 was 3 mm. In this case, since the molten metal did not adhere to the bore pin 14, it was possible to carry out casting of the discarded product three times and casting of the cylinder block 1 without any problem.

  The projecting portion 23 of the dummy liner 20 has a cross-sectional curve orthogonal to the axis O and is formed smoothly and continuously from the cylindrical portion 21 to the projecting portion 23 on the inner peripheral surface 22 of the cylindrical portion 21. . Thereby, the local deformation | transformation of the convex part 23 vicinity by solidification of the molten metal which flowed around the dummy liner 20 was suppressed, and it was suppressed that the dummy liner 20 deform | transforms and it becomes difficult to demold.

  In Example 1, the protruding portion 23 has a radius of curvature of a cross-sectional curve orthogonal to the axis O set to 1 to 3 mm from the inner peripheral surface 22 of the cylindrical portion 21 to the protruding portion 23 (the hem of the protruding portion 23). It had been. Thereby, the local deformation | transformation of the skirt (base of the convex part 23) of the convex part 23 was able to be suppressed. Moreover, as for the protrusion part 23, the curvature radius of the cross-sectional curve orthogonal to the axis line O was set to 1-5 mm in the top. As a result, the area where the protruding portion 23 and the bore pin 14 come into contact is suppressed, and the molten metal solidified between the protruding portion 23 and the bore pin 14 is prevented from adhering to the bore pin 14. It was possible to prevent the bore pin 14 from being damaged.

(Example 2)
Except for the radial gap 24 (one side) between the inner peripheral surface 22 of the cylindrical portion 21 of the dummy liner 20 and the outer peripheral surface 15 of the bore pin 14 being 2 mm, the discarded product and the cylinder block 1 I tried casting. Since the molten metal did not adhere to the bore pin 14, the casting of the discarded product and the casting of the cylinder block 1 could be performed without any problem.

(Example 3)
Except for the thickness of the cylindrical portion 21 of the dummy liner 20 being 2 mm and the radial clearance 24 (one side) between the inner peripheral surface 22 of the cylindrical portion 21 and the outer peripheral surface 15 of the bore pin 14 being 2 mm, the same as in Example 1. Attempts were made to cast the discarded part and the cylinder block 1. Since the molten metal did not adhere to the bore pin 14, the casting of the discarded product and the casting of the cylinder block 1 could be performed without any problem.

Example 4
Except that the thickness of the cylindrical portion 21 of the dummy liner 20 is 5 mm and the radial gap 24 (one side) between the inner peripheral surface 22 of the cylindrical portion 21 and the outer peripheral surface 15 of the bore pin 14 is 1 mm, the same as in the first embodiment. Attempts were made to cast the discarded part and the cylinder block 1. Since the molten metal did not adhere to the bore pin 14, the casting of the discarded product and the casting of the cylinder block 1 could be performed without any problem.

(Comparative example)
Except for the thickness of the cylindrical portion 21 of the dummy liner 20 being 5 mm and the radial gap 24 (one side) between the inner peripheral surface 22 of the cylindrical portion 21 and the outer peripheral surface 15 of the bore pin 14 being 0 mm, the same as in Example 1. Attempts were made to cast the discarded part and the cylinder block 1. Since it was confirmed that the molten metal was fixed to the bore pin 14 after the first casting of the discarded product, the experiment was stopped.

  According to the embodiment, the protruding portion 23 of the dummy liner 20 is brought into contact with the outer peripheral surface 15 of the bore pin 14, and the protruding portion 23 is excluded between the inner peripheral surface 22 of the cylindrical portion 21 and the outer peripheral surface 15 of the bore pin 14. It was confirmed that by forming the gap 24 and filling the radial gap 24 with the molten metal, the solidified molten metal can be prevented from adhering to the bore pin 14.

  The present invention has been described above based on the embodiments. However, the present invention is not limited to the above embodiments, and various improvements and modifications can be made without departing from the spirit of the present invention. It can be easily guessed. For example, the number, size, and shape of the protruding portions 23 and 33 and the recessed portions 35 can be set as appropriate. Although description is omitted in the above embodiment, both open deck type and closed deck type cylinder blocks can be manufactured. Moreover, although the case where the dummy bodies 20 and 30 were manufactured by cutting the tubular body obtained by extrusion molding or pultrusion molding was described, the present invention is not limited to this, and a dummy liner (tubular body) is manufactured by bending a plate material. Of course it is possible to do.

  In each of the above embodiments, the case where the dummy liners 20 and 30 are made of an aluminum alloy has been described. However, the present invention is not necessarily limited to this, and other metals such as steel can naturally be used. When a dummy liner other than an aluminum alloy is used, it is necessary to separate the dummy liner when re-processing the discarded product as a return material. However, the mold 10 can be preheated by casting the discarded product.

  In each of the above embodiments, the mold 10 in which the movable mold 11 forms a part of the deck surface side molding cavity 16a and the fixed mold 12 forms a part of the crank chamber molding cavity 16b has been described. It is not limited to this. It is naturally possible to manufacture the cylinder block 1 by using a mold in which a part of the deck surface side forming cavity 16a is formed by the fixed mold 12 and a part of the crank chamber forming cavity 16b is formed by the movable mold 11. is there.

  In each of the above-described embodiments, the case where the protruding portions 23 and 33 are formed in a protruding shape parallel to the axis O has been described. However, the present invention is not necessarily limited to this, and the protruding portions are not continuous in the axial direction. Of course, it is possible to make it convex. For example, three or more portions in the circumferential direction of one end edge in the axial direction of the cylindrical portion, and three or more portions in the circumferential direction of the other end portion are partially bent inward in the radial direction, and the end portions are bent. Of course, it is possible to use the protruding portions as a total of six or more locations. In this case, a cylindrical pipe material (extruded material or drawn material) is cut into a predetermined length, and a plurality of portions (at least three locations) at both end edges thereof are partially bent (indented) so that the protruding portions are formed. A dummy liner can be created.

  In each of the above-described embodiments, the dummy liners 20 and 30 that are curved surfaces in which the side surfaces of the cylindrical portions 21 and 31 are continuous have been described. However, the present invention is not necessarily limited to this. Naturally, it can be provided at 31. This is because the molten metal injected into the cavity 16 can be filled in the radial gap between the dummy liners 20 and 30 and the bore pin 14 through the hole. When the holes are provided in the cylindrical portions 21 and 31, it is preferable that the protruding portions can be formed next to the holes by forming the protruding portions in the cylindrical portions 21 and 31 by cutting and bending.

  In each of the above embodiments, the dummy liners 20 and 30 having the same cross-sectional shape perpendicular to the axis O in the axial direction have been described. However, the present invention is not limited to this. If the radial gap 24 can be formed between the cylindrical portions 21 and 31 and the bore pin 14, it is naturally possible to use dummy liners having different cross-sectional shapes perpendicular to the axis O in the axial direction. In this case, a dummy liner can be created by plastic working or casting.

  In the first embodiment, the axial end surface 26 of the dummy liner 20 and the fixed mold 12 (the bulging portion 18) contact each other (the axial gap 27 is 0 mm), or the end surface 26 and the fixed mold 12 (the bulging portion). 18), the axial gap 27 is formed, but the present invention is not necessarily limited to this. This is because, when the dummy liner 20 is long, the end surface of the dummy liner 20 sandwiched between the movable mold 11 and the fixed mold 12 can be crushed and clamped. After the dummy liner 20 is crushed, the axial gap 27 between the end face 26 and the fixed mold 12 (the bulging portion 18) is 0 mm. However, even if the axial gap 27 is not provided, the molten metal can be used as a bearing. It is possible to flow into the radial gap 24 while forming the wall 3.

In the second embodiment, the case where the concave portions 35 are formed at three positions of the protruding portions 33 has been described. However, the present invention is not necessarily limited to this, and the number of the concave portions 35 can be set as appropriate. In addition, the dummy liner in which the recessed part 35 is formed for every protruding part 33 can be formed by forming the recessed part 35, the protruding part 33, and the cylindrical part 31 simultaneously by plastic working (bending process) of a metal plate material.
<Others>
<Means>
The dummy liner of the technical idea 1 includes a first mold that forms part of the deck surface side molding cavity, a second mold that forms part of the crank chamber molding cavity, the second mold, and the first mold. Prior to casting an aluminum alloy cylinder block in which the cylinder liner is cast by a mold having an axial bore pin that is disposed between and in contact with the inner peripheral surface of the cylinder liner. A metal dummy liner that is cast instead of the cylinder liner until the temperature rises to a predetermined temperature, and a cylindrical portion into which the bore pin is inserted, and an inner peripheral surface of the cylindrical portion toward a radially inner side And a protruding portion that contacts the outer peripheral surface of the bore pin, and a radial clearance is formed between the inner peripheral surface of the cylindrical portion and the outer peripheral surface of the bore pin except for the protruding portion.
The dummy liner according to the technical idea 2 is the dummy liner according to the technical idea 1, wherein the protruding portion is formed in a ridge shape continuous in the axial direction of the cylindrical portion.
The dummy liner according to the technical idea 3 is the dummy liner according to the technical idea 1 or 2, wherein the cylindrical portion has an axial length and at least one of the first mold and the second mold that are clamped and a shaft. The length is set so that an axial gap is formed between the end face in the direction.
The cylinder block manufacturing method of Technical Idea 4 includes a first mold that forms a part of a deck surface side molding cavity, a second mold that forms a part of a crank chamber molding cavity, and the second mold. A cylinder block manufacturing method for manufacturing a cylinder block in which a cylinder liner is cast by a mold having a bore pin disposed between the first mold and contacting an inner peripheral surface of the cylinder liner, A cylinder liner is mounted on the bore pin and clamped in a state where the cylinder liner is disposed between the first mold and the second mold, and includes the deck surface side molding cavity and the crank chamber molding cavity. Prior to injecting the molten aluminum alloy into the cavity, a preheating step of raising the temperature of the mold until the temperature of the mold rises to a predetermined temperature is provided. The die clamping step of clamping the die liner in a state where the dummy liner according to any one of the technical ideas 1 to 3 is mounted on the bore pin and the dummy liner is disposed between the first die and the second die; By injecting the molten metal into the cavity formed by the mold clamping process, the molten liner is infiltrated between the outer peripheral surface of the bore pin and the inner peripheral surface of the cylindrical portion of the dummy liner, thereby casting the dummy liner. A casting process for casting a discarded article.
<Effect>
The dummy liner described in the technical idea 1 includes a first mold that forms a part of the deck surface side molding cavity, a second mold that forms a part of the crank chamber molding cavity, and the second mold and the first mold. Prior to casting an aluminum alloy cylinder block in which the cylinder liner is cast by a mold having a shaft-shaped bore pin that is disposed between and in contact with the inner peripheral surface of the cylinder liner, the temperature of the mold Until the temperature rises to a predetermined temperature. When the present inventors intentionally provided a gap (radial gap) between the inner peripheral surface of the metal dummy liner and the outer peripheral surface of the bore pin, the molten metal that has entered the radial gap does not adhere to the bore pin. I found.
According to this dummy liner, the protruding portion that protrudes radially inward from the inner peripheral surface of the cylindrical portion into which the bore pin is inserted is in contact with the outer peripheral surface of the bore pin. A radial gap is formed between the inner peripheral surface of the cylindrical portion and the outer peripheral surface of the bore pin except for the protruding portion. The molten metal is filled from the gap in the radial direction, and crystal grains are refined by contact with the bore pin and rapidly solidified, so that the solidified molten metal can be prevented from adhering to the bore pin.
In addition, the solidified product that has solidified due to the molten metal intruding into the radial gap has a thickness equivalent to the radial gap, so that a certain degree of strength can be secured, and the solidified product can be removed when removing the discarded product from the mold. Can be made difficult to collapse. As a result, it is possible to suppress the collapsed solidified product from being sandwiched between the thrown away product and the bore pin and being rubbed against the bore pin, so that the solidified product can be prevented from adhering to the bore pin.
As described above, the dummy liner prevents the solidified material from adhering to the bore pin by providing a radial gap between the bore pin and the molten metal to be positively filled with molten metal. There is no need to increase accuracy. Since the dimensional accuracy of the dummy liner can be relaxed, there is an effect that the cost of the dummy liner can be reduced.
According to the dummy liner described in the technical idea 2, the protruding portion is formed in a ridge shape that continues in the axial direction of the cylindrical portion. Since the cross-sectional shape orthogonal to the axial direction can be made the same across the axial direction, a dummy liner can be made by cutting a long object formed by extrusion molding or pultrusion molding. Therefore, in addition to the effect of the technical idea 1, there is an effect that the productivity of the dummy liner can be ensured.
Since the protruding portion is formed in a ridge shape that extends continuously in the axial direction of the cylindrical portion, a circumferential gap formed between the protruding portion and the protruding portion extends across the axial direction of the cylindrical portion. Can be provided. Since the solidified product of the molten metal that has entered the gap can be continued in the axial direction of the cylindrical portion, the solidified product can be further prevented from collapsing when the discarded product is removed from the mold. Therefore, in addition to the effect of the technical idea 1, the effect of not allowing the solidified molten metal to adhere to the bore pin can be further enhanced.
According to the dummy liner described in the technical idea 3, the axial length of the cylindrical portion is formed between at least one of the clamped first mold and the second mold and the end face in the axial direction. Is set to a length. Therefore, in addition to the effect of the technical idea 1 or 2, there is an effect that the molten metal can be easily poured into the radial gap from the axial gap between the axial end face of the dummy liner and the first mold or the second mold.
According to the cylinder block manufacturing method described in the technical idea 4, the first mold that forms part of the deck surface side molding cavity, the second mold that forms part of the crank chamber molding cavity, and the first A cylinder block in which the cylinder liner is cast is manufactured by a mold having a bore pin disposed between the second mold and the first mold and in contact with the inner peripheral surface of the cylinder liner. The cylinder liner is mounted on the bore pin, the mold is clamped with the cylinder liner disposed between the first mold and the second mold, and the molten aluminum alloy is formed in the cavity including the deck surface side forming cavity and the crank chamber forming cavity. Prior to injecting the mold, the mold is heated by the preheating process until the temperature of the mold rises to a predetermined temperature. Through the mold clamping process, the dummy liner described in any one of the technical ideas 1 to 3 is mounted on the bore pin, and the mold is clamped in a state where the dummy liner is disposed between the first mold and the second mold. A casting process in which the molten liner is cast between the outer peripheral surface of the bore pin and the inner peripheral surface of the cylindrical portion of the dummy liner by injecting the molten metal into the cavity formed by the mold clamping process. The product is cast. Thereby, there exists an effect similar to the technical idea 1.

1 Cylinder block 2 Cylinder liner 10 Mold 11 Movable type (first type)
12 Fixed type (second type)
14 Bore pin 15 Outer peripheral surface 16 Cavity 16a Deck surface side forming cavity 16b Crank chamber forming cavity 20, 30 Dummy liner 21, 31 Cylindrical portion 22, 32 Inner peripheral surface 23, 33 Protruding portion 24 Radial clearance 25, 26 End surface 27 Axial clearance

Claims (3)

A first mold forming a part of the deck surface side molding cavity, a second mold forming a part of the crank chamber molding cavity, and being disposed between the second mold and the first mold. Prior to casting an aluminum alloy cylinder block in which the cylinder liner is cast by a mold having a shaft-shaped bore pin in contact with the inner peripheral surface of the cylinder liner, the temperature of the mold rises to a predetermined temperature. A metal dummy liner that is cast instead of the cylinder liner,
A cylindrical portion into which the bore pin is inserted;
A protruding portion protruding radially inward from the inner peripheral surface of the cylindrical portion and contacting the outer peripheral surface of the bore pin;
A radial gap is formed between the inner peripheral surface of the cylindrical portion and the outer peripheral surface of the bore pin except for the protruding portion ,
The protrusion portion, the dummy cylinder liner according to claim Rukoto formed on ridge-like continuous over the axial direction of the cylindrical portion. The cylindrical portion has an axial length that is set such that an axial clearance is formed between at least one of the clamped first mold and the second mold and an end face in the axial direction. dummy cylinder liner according to claim 1 Symbol mounting, characterized in that there. A first mold forming a part of the deck surface side molding cavity, a second mold forming a part of the crank chamber molding cavity, and being disposed between the second mold and the first mold. A cylinder block manufacturing method for manufacturing a cylinder block in which a cylinder liner is cast by a mold having a bore pin in contact with an inner peripheral surface of the cylinder liner,
The cylinder liner is attached to the bore pin, and the mold is clamped in a state where the cylinder liner is disposed between the first mold and the second mold, and the deck surface side molding cavity and the crank chamber molding cavity are formed. Prior to injecting the molten aluminum alloy into the cavity, including a preheating step of heating the mold until the temperature of the mold rises to a predetermined temperature,
The preheating step is a mold clamping step in which the dummy liner according to claim 1 or 2 is attached to the bore pin and the dummy liner is disposed between the first mold and the second mold, and the mold clamping process is performed.
By injecting the molten metal into the cavity formed by the mold clamping process, the molten liner is infiltrated between the outer peripheral surface of the bore pin and the inner peripheral surface of the cylindrical portion of the dummy liner, thereby casting the dummy liner. A cylinder block manufacturing method comprising: a casting process for casting a discarded article.

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